1. Field of the Invention
The present invention pertains to respiratory interface devices for communicating a flow of gas with an airway of a user, and, in particular, to a respiratory interface device that includes a mask and a lever, where actuation of the lever moves a portion of the mask toward the patient.
2. Description of the Related Art
A variety of respiratory masks are known which cover the areas surrounding the nose and/or mouth of a human user and that are designed to create an effective fit against the user's face. Typically, gases can be provided at a positive pressure within the mask for consumption by the user. The uses for such masks include high altitude breathing (aviation applications), swimming, mining, fire fighting, and various medical diagnostic and therapeutic applications.
One requisite of many of these masks, particularly medical respiratory masks, is that they provide an effective fit against the user's face and that the mask contours with the user's face to limit or prevent leakage of the gas being supplied. A common type of mask incorporates a single-piece faceplate or a two-piece faceplate, having an upper portion (e.g., to cover the nasal portion of a human user's face) and lower portion (e.g., to cover the mouth portion of a human user's face) that are unitary or coupled together by a flexible member. See, for example, U.S. Patent Pub. 2011/0232647 the contents of which are incorporated herein by reference.
The respiratory masks that are known also have a sealing surface or cushion around the periphery of the mask to seal against the user's face. The cushion is typically attached to the faceplate. Such masks have performed well when the fit is good between the contours of the seal surface and the corresponding contours of the user's face. This may occur, for example, if the mask provides a good fit against the user's face and the mask contours with the user's face. If the fit is not good, there will be gaps in the mask-to-face interface resulting in gas leaking from the mask at the gaps. Considerable force will be required to compress the mask member to close the gaps and attain a satisfactory seal in those areas where the gaps occur.
Typically, this required force will be provided by straps that are connected to the mask to securely fit the mask to the face of the user. Such force is undesirable because it produces high pressure points elsewhere on the face of the user where the mask contour is forcibly deformed against the face to conform to the user's facial contours. This will produce considerable user discomfort and possible skin irritation and breakdown anywhere the applied force exceeds the local perfusion pressure, which is the pressure that is sufficient to cut off surface blood flow.
One area of the cushion that is prone to being spaced from the user's face is the area about the bridge of the nose. That is, it is not uncommon to have a gap between the cushion and the user's face at the bridge of the nose or adjacent the bridge of the nose. When such a gap occurs, the user may adjust the straps by tightening or loosening the straps, as discussed above, or by moving the position of the straps relative to the user's face. Typically, the user would move the straps to a higher position on their face. This adjustment, however, places the straps closer to the user's eyes, which is generally considered to be uncomfortable. Alternatively, the respiratory interface device may be provided with additional straps so as to allow for better positioning of the respiratory interface device relative to the user's face. Additional straps, however, are also generally considered to be uncomfortable.